Carton and method of sealing it



June 12, 1934. v c, KELLER I 1,962,660

CARTON AND METHOD OF SEALING IT Filed March 2:5, 1929 ASPHALT 0R BITUMENADHESIVE INVENTOR.

Maw azaww ATTORNEYS.

Patented June 12, 1934 UNITED STATES PATENT OFFICE Charles L. Keller,Cincinnati,

Ohio, assignor to The Richardson Company, Lockland, Ohio, a

corporation of Ohio Application March 23, 1929, Serial No. 349,477 4Claims. (Cl. 9336) 5 proof and grease resistant. Inasmuch as it is notpractical to coat cartons with these sub- If the portions were ofcomparatively large size, as for example the end sealing flaps ofcartons, the appearance of the completed and sealed carton would begreatly impaired. A still greater objection to the use of the abovemethods is that extra machines and handling are required to removeparafl'in from flaps in more than one direction. Indeed, to date, nosuch machine is in general use.

It is an object of my invention to provide an adhesive which will adhereto a paraflined surface and consequently a method of gluing knock downcarton blanks without the necessity of the provision of means forremoving paraflin or wax from any portions thereof.

It is an object of my invention to provide a glued knock down cartonblank in which the original waterand greaseproofness has been preservedand has notbeen impaired over any area by a method employed to removeparaflin or wax therefrom.

It is still'another object of my invention to provide a paraffinedfolding carton or other type of parafiined carton with sealing flaps,and a method of sealing such cartons after they have been filled, themethod not involving the necesused as a seal, and consequently in partat least as an adhesive, particularly in making the wax wrappersmentioned above; but the binding effect of paraffin is too weak topermit the satisfactory manufacture of cartons by any such practice. Theband of'adhesive along the glued flap in a carton blank is necessarilynarrow and must be quite strong. While somewhat less difliculty might beexperienced in sealing the end flaps of a carton with paraflin alone,nevertheless this has not been regarded as practicable in a cartonstructure which forms the sole container for the material being shipped.In all cases where paraflin has been used as a sealing medium, of whichapplicant has knowledge, sepbeen used over the cartons, and the wrappersthemselves have been heat sealed with paraffin. These and other objectsof my invention I accomplish by that certain process of which I shallnow describe an exemplary embodiment.

In the drawing: Fig. 1 is a perspective view of a carton to which myinvention isapplied; and Fig. 2 is a sectional perspective view of thesame.

Broadly my invention comprises the provision of an adhesive which willadhere to a paraflined surface either by amalgamation with the paraffinor otherwise. An exemplary type of such an tice may be stronger, thanthe internal strength of the board itself. This bond may be of twokinds. The preferable one is where the hot asphalt fluxes with theparafiin and penetrates to the actual surface of the board, so thatpressure on the gluing machine permits only a very thin layer ofasphalt-paraffin flux to remain and yieldv a fiber -to fiber bond asstrong or stronger than the paper itself. A less preferable,

but still practical, bond'results when a thicker layer of asphaltremains so that, although it may penetrate to the surface of the bond, afracture of the bond results insplitting the asphalt itself.

If the adhesive is an asphaltic substance, it is used hot and it may bethat beside the fiuxing action noted above, the hot application ofbituminous substance tends in some measure to drive the paraffin intothe board. It. is to be noted however, that whatever action occurs, overthe surface upon which the paraffin has thus been treated, there lies afilm of bituminous substance which is also waterproof andgrease-resistant, so that the proofness of the board is in nowiseimpaired.

My invention is not however restricted to the use of asphalt, butembraces'any equivalent substance which has the characteristic ofamalgamating with the paraflln which overlies the carton surface, andforming either by itself or with the paraffin, an adhesive layer of therequired strength. It embraces an adhesive which has the characteristicof penetrating through the paraffin layer and fastening on to thesurface of the material to be pasted. Its usefulness is not restrictedto the gluing of paraflined cartons but has application wherever it isdesired to stick together by adhesive action, two substances, at leastone of which has previously been treated with parafiin or wax. Thus ithas application to he manufacture of bags, pouches and all manner ofcontainers for hygroscopic goods, or goods which it is desired to sealin shipment against the effects of moisture, gases, grease and the like.

In an exemplary practice under my invention I employ as an adhesive anasphalt with Ball and Ring melting point of 150 to 160 degrees F.,penetration 100 grams, 5 seconds of around 20. This is an asphaltcommonly usedfor saturating felt for felt base floor covering. Iintroduce this asphalt into the glue pot of a standard gluing machine,the glue pot, as in standard practice,

being equipped with heating means generally of electric character. I runmy adhesive quite hot, say at 400-450 F. and I apply it to the cartonsin the ordinary manner. Thus it will be seen that the practice of myinvention makes no change excepting in the nature of the adhesive and inthe temperature at which it is kept, over ordinary practices in thegluing of carton blanks to form knock down folding cartons; nor are anyadditions to the gluing machine required, such as means separately toremove from the surfaces to be glued, their coating of paraffin or wax.Some care has to be taken with myprocess to see that after theapplication of the bituminous adhesive to one surface, that surface ispressed into contact with the surface to which it is to be glued, beforethe adhesive has lost its tackiness; and it is usually advisable toemploy some care in temperature control to prevent the dulling of theparafiin surfaces which fall adjacent in any. stage of the gluingoperation tothe heated band of adhesive. It goes without saying that theamount of adhesive should. be conto 215 degrees P.

application of hot bitumen,

trolled, just as in ordinary giving, to the end that there may be noexcesses to be squeezed out upon the carton surfaces. It is to bepointed out also that in some cases and with certain materials, I mayuse a solvent if desired in connection with my bituminous adhesive, andto the extent of the solvent used, dispense with the use of heat.

In these descriptions the term glu means the combining or pastingtogether of portions of paper or paper board cartons or containers withheat liquefiable orsoftenable adhesive material such as'asphalt, pitch,gums, resins, etc., and in the manner of and with the equipmentordinarily used for this purpose with water soluble adhesive such asanimal or destrin glues and the like.

Other examples comprises the use at 400 degrees F. of an air blownasphalt of a 200 Ball and Ring melting point, penetration 7'? degreesF., 100 grams, 5 seconds of 20 to 25, made from Mexican or Mexican andIllinois crude; the use at 500 degrees F. of fatty acid pitch of Balland Ring melting point 145 to 150 degrees F., penetration 77/100/5 ofaround 60; the use at 300 to 325 degrees F., of Montan wax; the use at420 degrees F. of orange flake shellac; the use of Carnauba wax at 320degrees F.; the use of sulphur at 265 degrees F.; the use at 300 degreesto 325 degrees F. of coal tar pitch with 160 to 1'10 degrees F. .Balland Ring melting point; etc. The kind of bitumen to be used forparaflined cartons will vary with the purpose to which the carton isapplied. An ice cream carton, for example, requires a type of bituminousadhesive that will not open upat cold or freezing temperatures; a buttercarton will not be frozen nearly so stifi; a cheese container may or maynot be subjected to very low temperatures; a coconut (shredded) cartonnever is frozen or chilled intentionally. Consequently, for thosecartons never chilled nor frozen the 20 penetration steam refinedasphalt or 25 penetration air blown asphalt will serve as an adhesive atroom temperatures but will not hold a good bond at cold temperatures.For

the chilled cartons a fatty acid or stearine pitch will hold the bond atlow temperatures, (if desired a flux of asphalt suitable bitumen can beused).

A typical soft fatty acid pitch is one with Ball and Ring melting point130435 deg. F., penetration '77/100/5 of 68, 32/200/60 of 29, 115/50/5and is quite soft.

In the sealing of cartons after filling, the practice of my inventionwill comprise the substitution of my type of adhesive for other types ofadhesive, the application thereof by the same means as at presentemployed, and the control of temperature as outlined above in connectionwith the pasting of knock down carton forms.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:-

1. That process of forming and sealing cartons of paperboard having asurface layer of wax, which comprises superposing the parts thereofwhich are to be joined adhesively with mutually facing surfaces, atleast one of which surfaces and stearine or other has the wax layer,and, without'previous removal of said wax, cementing said parts togetherby the miscible to, some extent at least with said wax,

permeating the wax surface layer, and having and thereby.

facing surfaces, at least one greater adhesive and cohesive propertiessaid wax.

than

2. That process of forming or sealing cartons of paperboard having asurface layer of wax. which comprises superposing the parts thereofwhich are to be joined adhesively with mutually of which surfaces hasthe wax layer, and, without previous removal of said wax, cementing saidparts together by the application of hot asphalt to said mutually facingsurfaces.

3. A carton formed of paperboard having a surface layer of wax, at leasttwo overlapping portions of the body of said carton with mu- I tualiyfacing surfaces, at least one of which said paperboard.

' CHARLES L. KELLER.

